Numerous mobile devices such as mobile phones and notebook-sized personal computers are utilized as a product using a rechargeable battery. The rechargeable battery is also attracting attention as a large-sized battery for an electric vehicle.
An electrode of the rechargeable battery is constituted by: a collector made of a metallic material such as copper or aluminum; and an active material layer bound onto the collector. The active material layer generally contains a binding agent as a binder for an electrode for binding an active material to the collector. In recent years, attempts to utilize polyacrylic acid that is an inexpensive polymer compound have been made as a binder for an electrode. Patent Document 1 discloses a binder for an electrode, the binder containing a lithium salt of polyacrylic acid or a sodium salt of polyacrylic acid. Patent Document 2 discloses a binder for an electrode, the binder containing polyacrylic acid and polyethyleneimine. Patent Document 3 discloses a binder for an electrode, the binder containing polyacrylic acid and an amine compound.